The goal is to get a single group of as many apples touching as possible. Any settings are allowed. Any level is allowed. The only rule is the entire group of apples must be touching.
As an example, if you have one group of 3 apples, and one group of 2 apples, your score is 3 (not 5) since the most apples touching in a single group is 3.
For those who really want the mathematical semantics perfect, a group of touching apples is defined as follow. Pick an apple. All apples immediately touching it on the left, right, up, or down sides are considered to be touching and part of its group. Next, take all those touching apples, likewise any apples touching them on their up, down, left, or right are also part of the group. Continue this process until no new apples can be considered to be part of the group. Count the total number of apples in this group. That is your score